Resistance to macrolide, lincosamide and streptogramin antibiotics in staphylococci isolated in Istanbul, Turkey

The purpose of this study was to investigate the prevalence and genetic mechanisms of erythromycin resistance in staphylococci. A total of 102 erythromycin resistant non-duplicate clinical isolates of staphylococci [78 coagulase negative stapylococci (CNS), 24 Staphylococcus aureus] were collected between October 2003 and August 2004 in Istanbul Faculty of Medicine in Turkey. The majority of the isolates were from blood and urine specimens. Antimicrobial susceptibilities were determined by the agar dilution procedure and the resistance phenotypes by the double disk induction test. A multiplex PCR was performed, using primers specific for erm(A), erm(B), erm(C), and msrA genes. Among the 78 CNS isolates, 57.8% expressed the MLSB-constitutive, 20.6% the MLSB-inducible, and 21.6% the MSB phenotypes. By PCR, 78.2% of these isolates harbored the erm(C) gene, 8.9% erm(A), 6.4% erm(B), and 11.5% msrA genes. In S. aureus, the constitutive MLSB (58.3%) was more common than the inducible phenotype (20.8%). erm(A) was detected in 50% and erm(C) in 62.5% of the isolates, while 37.5% contained both erm(A) and erm(C). erm(C)-associated macrolide resistance was the most prevalent in CNS, while erm(C) and erm(A, C) was the most prevalent in S. aureus.     

fur (-) mutation increases the survival time of Escherichia coli under photooxidative stress in aquatic environments

We investigated the survival of the wild type Escherichia coli (QC771) and fur- mutant strain (QC1732) under photooxidative stress in different water sources. The survival of fur- mutant and wild type E. coli was seen as a significant decrease in the visible light samples in the presence of methylene blue (MB). The fur-E. coli strain lived longer than the wild type E. coli strain on exposure to MB and visible light, which generates singlet oxygen, in both lake water (48-h) and pure water (16-h). It is interesting to note that the survival of both wild type and the fur- mutant strain was more protected at 24 °C than at other temperatures. The Fur protein does not have any relation to the entry of E. coli into the viable but nonculturable state (VBNC) under photooxidative stress. This is the first study which shows that fur- mutation increases the resistance of E. coli to photooxidative stress in aquatic environments, and the Fur protein does not have any relation to the entry of E. coli into the VBNC state.     

Isolation of methicillin-resistant Staphylococcus aureus from caprine mastitis cases

There is no report on isolation of methicillin-resistant Staphylococcus aureus (MRSA) strains from mastitis infection in goats. This study reports two MRSA strains that were isolated from caprine mastitis. A total of 42 Staphylococcus aureus (S. aureus) strains collected from caprine mastitis cases between 2008 and 2009 were examined. Two (4.8%) out of 42 S. aureus strains were identified as MRSA by Kirby–Bauer disc diffusion and mecA polymerase chain reaction (PCR) methods. Based on the coa gene polymorphism, the goat strains were grouped into 6 types. By using rapid amplified polymorphic DNA (RAPD) assay, 10 different patterns were obtained from 42 S. aureus strains, and strains were located in 6 sub-groups. A total of 71% (n = 30) of the strains were clustered in one main group and placed 4 sub-groups by RAPD assay. The two MRSA strains produced identical patterns and distinguished from other S. aureus strains by RAPD method. This paper is the first report of MRSA isolation from caprine clinical mastitis cases.     

Xanthoria elegans (Link) (lichen) extract counteracts DNA damage and oxidative stress of mitomycin C in human lymphocytes

Several lichen species have been used for medicinal purposes throughout the ages, and they are reported to be effective in the treatment of different disorders including ulcer and cancer. It is revealed that lichens may be easily accessible sources of natural drugs and possible food supplements after their safety evaluations. The main objective in this study was to evaluate the roles of aqueous extracts of Xanthoria elegans (at 25, 50 and 100 μg/ml) upon mitomycin C (MMC; at 10⁻⁷ M) induced genotoxic and oxidative damages in cultured human lymphocytes. X. elegans were collected from the Erzurum and Artvin provinces (in Turkey) during August 2010. After the application of MMC and X. elegans extract (XEE), separate and together, human whole blood cultures were assessed by four genotoxicity end-points including chromosomal aberration, micronucleus, sister chromatid exchange (SCE) and 8-oxo-2-deoxyguanosine (8-OH-dG) assays. In addition, biochemical parameters [total antioxidant capacity (TAC) and total oxidative stress (TOS)] were examined to determine oxidative effects. According to our results, the frequencies of cytogenetic endpoints and 8-OH-dG levels were significantly increased by MMC compared with controls in human peripheral lymphocytes. MMC caused oxidative stress by altering TAC and TOS levels. On the contrary, XEE led to increases of TAC level without changing TOS level. XEE had no genotoxic effect. Furthermore, our findings revealed that MMC induced increases in the mean frequencies of four genotoxic indices were diminished by XEE in dose dependent manner, indicating its protective role towards cells from MMC exerted injury. In conclusion, the results obtained in the present study indicate for the first time that XEE is a potential source of natural antigenotoxicants.     

Regulation of FAS ligand expression by chemokine ligand 2 in human endometrial cells

Human endometrium is a dynamic tissue under the influence of numerous hormones, growth factors, and cytokines interacting to maintain a balance of cellular growth, differentiation, and apoptosis. We have previously demonstrated that several factors including interleukin-8, extracellular matrix, and steroid hormones modulate FASLG, one of the apoptotic molecules, in human endometrium. Chemokine ligand 2 (CCL2), a monocyte chemoattractant and activating factor, is a cytokine involved in endometrial function. CCL2 is elevated in the peritoneal fluid of women with endometriosis. We hypothesize that increased levels of CCL2 in the endometriotic environment may upregulate FASLG expression in human endometrial stromal cells and induce a local immunotolerance in endometriosis. To test our hypothesis, we studied the in vitro regulation of FASLG expression and apoptosis by CCL2 in endometrial stromal cells. Western blot analysis revealed that CCL2 upregulated FASLG protein expression in cultured endometrial stromal cells. Based on semiquantitative RT-PCR analysis, CCL2 did not alter either FAS or FASLG mRNA expression in endometrial stromal cells. Immunocytochemistry results from the same cells treated with CCL2 demonstrated upregulation of FASLG protein expression. CCL2 did not change rate of apoptosis in endometrial stromal cells as evaluated by TUNEL assay. However, an increased apoptotic rate was detected in Jurkat (T lymphocytes) cells cocultured with endometrial stromal cells previously treated with CCL2. We speculate that increased FASLG expression by CCL2 may induce apoptosis of T lymphocytes and thus produce an immunotolerant environment for the development of ectopic implants.     

Bone metabolism in ovariectomized rats with induced hyperthyroidism: the effect of estrogen replacement

We aimed to investigate whether or not the estrogen is playing any role in the effect of thyroid hormones on bone metabolism. The rats were divided into five groups. In the first group L-thyroxine-induced hyperthyroid rats were ovariectomized (OVX) while the OVX rats were administered L-thyroxine in the second group. 17beta-Estradiol (E2) was replaced in OVX rats in Group III. L-thyroxine and E2 were simultaneously administered to OVX rats in Group IV. The fifth group received sham operation. Blood samples taken from the tail vein of rats were analyzed for plasma T3, T4, TSH and serum interleukin (IL)-1beta, IL-6, tumor necrosis factor (TNF)alpha, calcium (Ca), phosphorous (P), parathyroid [corrected] hormone (PTH), alkaline phosphatase (t-ALP), bone-specific alkaline phosphatase (b-ALP) and E2. The levels of cytokines, t-ALP and b-ALP increased but PTH decreased, while there was no change in Ca and P levels in L-thyroxine-administrated rats. However, the levels of cytokines, Ca, P, PTH, t-ALP and b-ALP did not change in L-thyroxine-administered OVX rats. In OVX rats, the cytokines, t-ALP and b-ALP increased while Ca, P remained the same, but PTH decreased. L-thyroxine administration to OVX rats did not change the cytokines, Ca, P, PTH, t-ALP and b-ALP levels. The replacement of E2 in OVX rats decreased the cytokines, t-ALP and b-ALP values, increased PTH levels while there was no change in Ca and P. L-thyroxine and E2 administration to OVX rats increased the cytokines, t-ALP and b-ALP levels and decreased PTH, but Ca and P remained the same. In sham-operated rats, there was no change in all parameters compared to initial values. This study suggests that estrogen may play a role in the effects of thyroid hormones on bone metabolism.     

Ghrelin is present in human colostrum, transitional and mature milk

Ghrelin and its mRNA have recently been found in numerous human tissues including breast. The aim of this study was to compare the ghrelin levels in colostrum, mature and transitional milk and plasma in lactating women with plasma samples from non-lactating women. Venous blood samples were obtained from 17 healthy lactating women aged 22-35 years and from 16 age-matched controls. Colostrum, transitional and mature milk samples were collected just before suckling. The level of bioactive ghrelin was determined by RIA. Comparison of ghrelin values for lactating women showed significantly lower concentrations in colostrum (70.3 +/- 18 pg/ml), transitional milk (83.8 +/- 18pg/ml) and mature milk (97.3 +/- 13 pg/ml) than in the corresponding plasma samples (first day 95 +/- 16 pg/ml, 10th day 111 +/- 13 pg/ml and 15th day 135 +/- 16 pg/ml). The plasma concentrations were lower in the lactating than in the non-lactating women. Thus, the ghrelin levels in colostrum, transitional and mature milk were elavated concomitantly with increasing plasma ghrelin after delivery. The origin of milk ghrelin is not known, but it probably comes from the plasma.     

The influence of continuous exposure to 50 Hz electric field on nerve regeneration in a rat peroneal nerve crush injury model

The effect of power frequency electric field (EF) on nerve regeneration was investigated on a rat peroneal nerve crush injury model. The animals were assigned to three groups: 50 Hz EF and Static EF groups were exposed at 10 kV/m. The sham group was kept in the same setting without any EF applications. EF was uninterruptedly applied for 21 days postoperatively. Repeated measures analysis of daily walking tracks during EF exposure demonstrated lower toe spread recovery (TSR) in the 50 Hz EF group. Significant difference across the groups was found only at days 7, 8, 12, 16, 17, 20, and 21 when TSR was analyzed for each measurement time. Print length recovery and peroneal function index did not differ across the groups. Walking track parameters were found to recover to their baseline values by day 28 in all groups. Day 14 but not day 21 measurements revealed smaller nerve cross-sectional area, lower total regenerating axon area, and higher mean myelin debris area in 50 Hz EF group. Both day 14 and 21 measurements revealed higher total myelin debris area, lower EDL muscle weight, and lack of significant enlargement in nerve cross-section distal to the injury, compared to the normal counterpart in 50 Hz EF group. All differences were in keeping with lower rates of Wallerian degeneration and nerve regeneration in 50 Hz EF group. When walking track, histomorphometry and muscle weight are considered individually, their differences across the groups may appear to be subtle to derive a conclusion for a 50 Hz EF effect. However, their concordance with each other in direction of effect suggests that continuous 50 Hz EF exposure has a weak effect that is detrimental mostly to the rate of early nerve regeneration in this axonotmetic injury model. Recovery of walking tracks was not different between Static EF and Sham groups. This suggests that the surface charges that may indirectly affect walking behaviors of the rats, do not account for the lower recovery of TSR in 50 Hz EF group. Differences in nerve regeneration between 50 Hz EF and Static EF groups suggests that electric induction may be required for pure EF effects even though the estimated density of induced fields is not above the endogenous background level for the 50 Hz EF exposure in this study.     

Effects of brassinosteroid on cotton regeneration via somatic embryogenesis

Brassinolide (BR), which is the most biologically active brassinosteroid, was used to examine the potential effect of hormone on cotton somatic embryogenesis. Ten-day-old cotton (Gossypium hirsutum L., cv. Cooker) seedlings were used for explant source and hypocotyls were removed and cultured on MS basal medium with B₅ vitamins supplemented with 1 mg/L 6-benzylaminopurine + 0.5 mg/L kinetin for callus induction. After one month proliferating calli pieces were collected and cultured on MS basal medium containing various concentrations of BR (0.1, 0.5, 1.0 μM) with their controls. BR treatments were negatively effective on the fresh weight of calli when compared to control. Differential somatic embryogenesis maturation rates due to BR treatment were observed. Somatic embryogenesis was stimulated especially for transition to cotyledonary phase at 0.5 mg/L BR. Histological preparations from embryogenic calli and somatic embryos at different stages of development revealed the spontaneous polyploidisation during early somatic embryogenesis on BR-treated calli. Present results suggest that BR negatively effected calli growth, however, had a stimulating role in maturation of somatic embryos.     

The Modified Sequential Treatment Regimen Containing Levofloxacin for Helicobacter pylori Eradication in Turkey

Background:  Eradication rates of Helicobacter pylori have declined to unacceptable levels in recent years. New and effective treatment options are warranted both as a first and second line treatment.
Aim:  To test an effectiveness of modified sequential therapy with levofloxacin for H. pylori eradication in Turkey.
Material and Methods:  Helicobacter pylori infected dyspeptic patients were included to the study. Subjects were treated with modified sequential therapy consisting of rabeprazole 20 mg b.i.d. and amoxicillin 1 g b.i.d., for 7 days followed by rabeprazole 20 mg b.i.d, levofloxacin 500 mg q.d. and metronidazole 500 mg b.i.d for the remaining 7 days.
Results:  Sixty-three treatment naive patients and 37 previous treatment failures were enrolled to the study (59 F, 41 M, age: 21–80 years). There was five drop out. Helicobacter pylori eradication was achieved in 80 patients, intention-to-treat (ITT): 80% (95% CI: 71–87%) and per-protocol (PP): 84.2% (95% CI: 75–91%), totally. In treatment naive patients ITT and PP eradication rates were 82.5% (95% CI: 71–91%), and 86.7% (95% CI: 75–94%), respectively. As a second line treatment eradication was successful in ITT 75.7%.(95% CI: 59–88%), and PP 80% (95% CI: 63–92%).Mild side effects were reported by 8 patients (8.4%).
Conclusions:  Sequential therapy using "rabeprazole and amoxicillin 7 days followed by rabeprazole, metronidazole and levofloxacin for 7 days" is a new regimen with acceptable eradication rates in naïve patients in Turkey. Further modifications in the dose or duration of this new sequential therapy might increase its effectiveness as both first and second line treatment.